Secondary intention healing time of postoperative surgical cancer skin wounds with a biosynthetic porcine type I collagen dressing. A 306-patient retrospective, observational study A. Gavillero Martín; M Juliá Roca; I. Serra-Guillén; A Rodríguez-Hernández; E. Manrique-Silva; A.E. López-Sundh; E Nagore Enguídanos;